On Sat, 21 Apr 2012 17:33:54 -0500, tom wrote:

On 4/21/2012 5:23 PM, Jeff Liebermann wrote:
For some irrational reason, that probably defies logical
justification, I've decided to setup my PCR1000 receiver as an
internet accessible receiver. There are about 7 programs available to
do this, so I don't expect software to be a problem. The receiver
will eventually be moved to a mountain top repeater site, which
unfortunately does not have much room for an antenna. The receiver
will tune from 0.1 to 1300Mhz. I don't wanna deal with an antenna
tuners or switches.

Is there an antenna or combination of antennas that are suitable for
such a wide tuning range and that is small enough to fit in a limited
rooftop area?

One thing not to forget is there are relatively inexpensive
duplexers/triplexers/etc. from the likes of Comet and others. Or roll
your own.

I like to make my own diplexer/triplexer boxes. In this case, only a
diplexer is needed. The Radio Shack discone antenna will (allegedly)
work from 30-1300MHz.
http://www.radioshack.com/graphics/uc/rsk/Support/ProductManuals/2000043_PM_EN.pdf
Below 30MHz is the real problem. Also, none of the commercial
diplexers I could find had a 30MHz cutoff frequency. Looks like I get
to build something.

I know that doesn't help much on the low end of things but means a
couple discones on the mid and upper will do well.

I've compared the performance of discones and biconical antennas.
Biconicals are better because the radiation pattern is towards the
horizon, instead of towards the sky. It also has about 1-2dB more
gain. However, I'm not in the mood for building yet another
mechanical marvel, and will probably use the discone.

And yes there will be some small to medium gaps because of the device.

I can probably ignore the TV bands (54 to 700MHz) but I want most
everything else.

Thanks much.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 4/21/2012 10:23 PM, Jeff Liebermann wrote:

I like to make my own diplexer/triplexer boxes. In this case, only a
diplexer is needed. The Radio Shack discone antenna will (allegedly)
work from 30-1300MHz.
http://www.radioshack.com/graphics/uc/rsk/Support/ProductManuals/2000043_PM_EN.pdf
Below 30MHz is the real problem. Also, none of the commercial
diplexers I could find had a 30MHz cutoff frequency. Looks like I get
to build something.


I have one and have never bothered to check it because I've never
actually used it. It's one of my backup backup antennas.

Time to test it.

tom
K0TAR

On Sat, 21 Apr 2012 20:23:04 -0700, Jeff Liebermann
wrote:

gain. However, I'm not in the mood for building yet another
mechanical marvel, and will probably use the discone.


discones are fine, but like to pick up static.

w.

In message , Helmut Wabnig
writes
On Sat, 21 Apr 2012 20:23:04 -0700, Jeff Liebermann
wrote:

gain. However, I'm not in the mood for building yet another
mechanical marvel, and will probably use the discone.


discones are fine, but like to pick up static.

Any more than any other vertical antenna (or even ANY antenna)?
--
Ian

On Sun, 22 Apr 2012 10:34:23 +0200, Helmut Wabnig [email protected] ---
-.dotat wrote:

On Sat, 21 Apr 2012 20:23:04 -0700, Jeff Liebermann
wrote:

gain. However, I'm not in the mood for building yet another
mechanical marvel, and will probably use the discone.

discones are fine, but like to pick up static.
w.

Static electricity or radio static noise? Static electricity should
not be a problem as the PCR1000 probably has a 100K resistor across
the antenna connector. This is standard on most radios. If not, I
can easily add one to bleed off any excess charge.

At VHF frequencies, any generated radio static should not be a
problem. The building is high enough that it might end up inside a
thunder cloud, where precipitation static might cause trouble.
Besides, there's not enough dielectric material on the discone to
build up much of a charge. If the humidity is low enough and the wind
speed high enough to create arcing, I'll have much bigger problems
than to deal with than a little static noise.

However, there may be another problem. We try to use grounded and low
impedance antennas on mountaintop sites in order to reduce induced
currents from nearby lightning hits. Both my proposed antennas are
ungrounded and/or fairly high impedance. Oh-oh.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558